Question

Perhatikan grafik fungsi kuadrat berikut! Tentukan :
a. Persamaan sumbu simetri!
b. Nilai Minimum!
C. Koordinat Titik minimum!
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Answer 1

PEMBAHASAN

Fungsi Kuadrat

• memotong sumbu x di (-3,0) dan (8,0)

y = a(x - x1)(x - x2)

y = a(x - (-3))(x - 8)

y = a(x + 3)(x - 8)

• melalui (0,-24)

-24 = a(0 + 3)(0 - 8)

-24 = -24a

a = 1

fungsi kuadrat :

y = (x + 3)(x - 8)

xp = (x1 + x2)/2

xp = (-3 + 8)/2

xp = 5/2

Nilai minimum

= yp

= (5/2 + 3)(5/2 - 8)

= 11/2 × (-11/2)

= -121/4

= -30 1/4

= -30,25